On a recent research voyage conducted
by the National Oceanic and Atmospheric Administration (NOAA) in the
Northwestern Hawaiian Islands (NWHI), scientists had a surprise encounter
with a monk seal at a depth of over 1,600 feet. The mission, conducted
by NOAA’s Office of Ocean Exploration, is designed to investigate
how endangered Hawaiian monk seals use shallow and deep-water habitats
for hunting and protection. NOAA is an agency of the U.S. Department
of Commerce.

Frank
Parrish, a fishery biologist with NOAA’s Pacific Island Fisheries
Science Center, was on the lookout for Hawaiian monk seals when he
sailed with a multidisciplinary team of scientists on the University
of Hawaii's Research Vessel Ka'imikai-o-Kanaloa (Heavenly
Searcher of the Seas). Scientists were supported by Hawaii Undersea
Research Laboratory (HURL) and its deep-sea manned submersibles Pisces
IV and V, a remotely operated vehicle (RCV-150) and
a Seafloor Sonar Mapping System.

“In previous studies, monk seals
had been tagged to signal a satellite when they surfaced, and we found
they were showing up in clusters,” said Parrish. “Some
clusters were easily explained, but some were distant with only the
deep ocean below. Those areas were ripe for exploration.” Parrish
surmised that monk seals clustered over deep ocean seamounts populated
with a diverse community of deep-sea coral and other invertebrates,
and used the corals as reference points for foraging in the area,
or as a habitat for feeding.

“We know gold coral fluoresces
when something brushes against it,” said Parrish. “If
an eel or other food source in coral is disturbed by a monk seal,
the coral ‘lights up’ and that could be like ringing the
dinner bell for a monk seal.”

In 1998, National Geographic deployed
research cameras, or “Crittercam”, on Hawaiian monk seals.
“We saw what the seals saw as far as light penetrated the ocean
to about 300 meters in what’s called the ‘photic’
layer,” said National Geographic’s Patrick Greene. On
this expedition we hoped to document a connection between monk seals
and deep ocean coral communities,” he said.

On a dive below 500 meters (approximately
1,640 feet), the submarine’s lights lit up the area as Amy Baco-Taylor
from Woods Hole Oceanographic Institution and HURL’s submersible
pilot, Terry Kerby, prepared to collect corals growing on the side
of vertical carbonate wall

The sub fought a strong and persistent
current trying to set its port side hard into the wall. Kerby powered
the thrusters to gently set the sub against the wall and let the current
move the sub down the wall until he steadied the sub on the edge of
a specimen collection box. Co-pilot Max Cramer took the thruster controls
to hold the sub in this precarious position while Kerby positioned
a camera and used the sub’s mechanical arm to pluck a twig from
a precious coral tree and stuff it into a jar in the specimen box.

“From the submarine’s portside
viewport, I noticed some movement,” said Cramer“In a fraction
of a second the shadow filled the entire viewport, about six inches
from my dropping jaws. ‘It’s a monk seal,’ I hollered,
firmly believing I’d be the only one to see the magnificent
animal at a depth, and in a deep-sea coral field, as never before
witnessed.”

Kerby and Baco-Taylor snapped their heads
to their viewports. “I couldn’t believe it,” said
Baco-Taylor. “I thought he was joking. Then I saw him. He had
just looked into Terry’s viewport, then swam a little further
and looked into my viewport at me! He showed no sign of stress if
he was out of his depth range, He was clearly comfortable and took
his time checking us out,” she said“I saw the mark A-12
very clearly before he swam away.”

A-12
was tagged this summer on Lisianski Island in the NWHI chain as part
of NOAA’s National Marine Fisheries Service’s protected
species investigation, and was observed about 350 miles from where
the animal was tagged.

“I believe it’s the first
time a monk seal was seen to be associated with deep-sea precious
corals and the first time a monk seal was seen from a submarine at
such a depth,” said Parrish.

Monk
seal in Hawaiian is “ilio-holo-kai” or “the
dog that runs in the sea.” There are only three known species
of monk seals, the most primitive of pinnipeds. The Caribbean monk
seal is extinct. About 500 Mediterranean monk seals and 1,200 to 1,400
Hawaiian monk seals are listed as endangered.

NOAA's Office of Ocean Exploration coordinates
and funds interdisciplinary voyages of discovery to map and explore
the ocean at new scales, develop a more thorough understanding of
ocean dynamics and interactions, develop new sensors and systems,
and share the excitement of discovery with the public. Outreach and
education activities associated with NOAA-sponsored missions to the
NWHI include K-12 lesson plans, mission summaries and explorer biographies
on NOAA’s Office of Ocean Exploration Web site.

NOAA is dedicated to enhancing economic
security and national safety through the prediction and research of
weather and climate-related events and providing environmental stewardship
of our nation's coastal and marine resources.